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Wider Fov with a 28 mm and wrong adapter!
  • AlbertZAlbertZ

    I've bought a Pentax K Mount lens (28mm) and since I haven't yet an adapter ring pk-mount -> m4/3, I've tried to use directly on my gh1 with an adaptor FD-m4/3. Of course, the adaptor doesn't fit correctly but..if you watch the result just holding the lens attached to the ring,you will able to focus and...you will get a remarkable WIDER FoV than 50mm eq (28x1.8 on gh1)!!! Anyone could explain me the reason?

  • 6 Replies sorted by
  • balazerbalazer

    Putting the lens closer to the camera makes the image circle smaller and reduces the focal length. It also shifts the focus range away.

  • AlbertZAlbertZ

    thanks @balazer, it could be a ghetto-trick to get a cheap fast wide lens ;) what are the main drawbacks however? it will be more difficult to focus close subjects, but at the same time it should be easier to achieve a "deep focus" look...is it?

  • p_hawksp_hawks

    your focus marks will be off, so if you go by those, that could be an issue, but as far as I know, if would be the opposite of a macro ring. Really wish I had a 3D printer right about now so that I could make some adapters and see how everything works through trial and error

  • fatpigfatpig

    @p_hawks: even better idea would be CNC machining :) @AlbertZ: can you get infinity focus? If yes, one could build such an adapter for daily use.

  • AlbertZAlbertZ

    Yes, I can get infinity focus :) @fatpig @p_hawks Yes, focus marks are off, but I don't care about them ;)

  • AlbertZAlbertZ

    I think I will modify directly a fd adapter! ;) the Fov seems to me close to 30mm (so the lens performs as a 18mm 2.8). Quite good wide open, but it's impossible to focus at 0,5 m. perfect for interior scene...and it's damned cheap!

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